It is known to have electrical disconnects between high amperage, high voltage power supplies and the electrical loads they serve. It is particularly desirable to have a compact such device in an electric vehicle to isolate the battery from the electric drive and control systems particularly during maintenance of such systems or the battery. Disconnects used heretofore for high amperage, high voltage systems have typically utilized bulky manual switches housed in locked boxes. Such switches and the housings therefor are undesirable in applications, such as electric vehicles, where volume, weight and operating environment are important considerations. Any electrical disconnect in an electric vehicle must not only have low mass and low volume, but must be simple to operate, essentially foolproof and capable of operating in an automotive environment which is subject to vibrations, corrosion and wide temperature variations.
It is an object of the present invention to provide a compact (i.e., low volume/mass) high voltage, high ampacity, simple to use, foolproof quick disconnect which is capable of operating in an automotive environment. This and other objects and advantages of the present invention will become more readily apparent from the detailed description thereof which follows.
This invention comprehends a compact high voltage, high ampacity quick disconnect for alternately manually connecting and disconnecting an electrical power supply to/from an electrical load. The invention is particularly useful in electric vehicles, but may also be used in other applications. The quick disconnect includes an input terminal receiving electrical current from the supply, and an outlet terminal receiving electrical current from the input terminal for delivering it to the load. The terminals are spaced apart from each other and each comprises an electrically conductive sleeve embedded in an insulating material and defining opening adapted to snugly receive a common electrical conductor which serves to electrically couple the terminals to each other. The terminals are held juxtaposed, albeit spaced apart, in an insulating housing such that the axes of their respective openings are aligned one with the other. A conductor whose external shape substantially conforms to the shape of the openings is movable in the direction of the axes of the openings for engaging and disengaging the sleeves to effect such electrical coupling and uncoupling. A nonconductive handle engages one end of the conductor for moving the conductor into and out of engagement with the sleeves. The conductor will preferably be a cylindrical copper rod having a diameter smaller than the IEC's standard finger.
The sleeves, which are electrically connected to input and output cables, preferably comprise a bundle of parallel wires joined together at their ends and capable of expanding radially to snugly engage a conductor inserted therein. The wire bundle will preferably be necked down at a location mid-way between the ends of the wires such that the sleeve has a generally hyperbolic or hour-glass shape. The necked down portion of the sleeve is smaller than the outside diameter of the conductor but is readily expansible when the conductor is inserted therein. Once expanded the sleeve will constrictively engage the outer surface of the conductor over substantially the entire length of the sleeve hence resulting in a low resistance electrical connection therebetween. Preferably, the wires comprising the sleeves are skewed with respect to the central axis of the sleeve with which they are associated such that the sleeve has a helical configuration. Most preferably, the wires are flat so that a large surface area thereof will engage the conductor for maximum low resistance conductivity through the switch. Such helical, hyperbolic connectors are per se known in the art, but have not heretofore been used in the manner described herein.
The handle comprises a fingergrip portion and a flange portion overlying a substantial portion of the housing embedding the terminals. A collar depends from the flange circumscribes one end of the conductor and mates with a well in the housing. At least one dog projects from the collar for engaging an undercut shelf in the housing adjacent the well upon insertion of the conductor into the sleeve and rotation of the handle so as to lock the conductor in position and prevent extraction thereof from the housing. The collar engages an auxiliary switch positioned in the housing for signaling or initiating other electrical disconnects, when the conductor is engaged or disengaged and hence the connectors coupled or uncoupled.
The quick disconnect will preferably include an elastomeric seal sandwiched between the flange on the handle and the upper surface of the housing to prevent incursion of contaminants (e.g., dirt, moisture, etc.) into the housing and the terminals embedded therein. Most preferably, the perimeter of the seal will extend beyond the periphery of the housing and engage the structure surrounding the housing for still further protection of the disconnect from contamination.